The New Mobile Broadcast via AoIP
Comrex has a long history in this category and the Access portable, while not a new product, continues getting new features added as time goes along. It's a full-duplex codec, with one line/mic level input, and a headphone mixer built-in. While it has an integral Ethernet connector, it also has a cardbus slot and a USB port that will fit various specific modems that will communicate via POTS, Wi-Fi (802.11b, g or n), Wimax, 3G and 4G (LTE). On the far end you would have another Access, either a portable or a rack mount unit. (If you use the POTS modem, Access is backward-compatible with legacy Comrex POTS codecs (except for Hotline).) By the way, when using that cardbus slot or USB port, you can make use of the Ethernet connection for Internet sharing. Network interfaces can be set for static IP addresses or set to use DHCP. The Access portable also has a built-in Web browser, so that you can log-in to access points as necessary. Access comes with the Comrex BRIC algorithms, and MPEG4/AAC algorithms. Another option is the five-channel mixer, which plugs in to the side of the Access portable, and gives you an additional five mic/line level inputs, and an additional five headphone outputs as well.
Another option for a small, portable remote device is the Tieline G3 Commander field unit. This device has two mic/line level inputs along with a single unbalanced input (RCA connector); it has two balanced outputs, and one unbalanced (RCA) out. It has built-in headphone mixing, with the separate headphone outputs. Via plug-in modules that go in to an expansion slot, you can communicate (in a full-duplex fashion) via IP, 3G, ISDN, X.21, and even BGAN (for satellite uplinking). IP interfaces can be configured for static IP or DHCP. A new plug-in module just being introduced is for 4G (USB style) modems. The far-end device back at your studio HQ would be another Tieline Commander. The Commander comes with the Tieline Music and MusicPlus algorithms in addition to G.711, G.722 and MPEG layer II. According to Tieline, the MusicPlus algorithm will provide 20kHz of stereo audio capability with data rates as low as 96kb/s. You also get the free Tieline Toolbox PC software configuration and control software, offering configuration, audio routing and input control of your local and remote codec.
While considering different manufacturers for a field unit, you may want to take a look at Scoopy from Aeta. This device has three mic/line inputs (with built-in limiters); two headphone outs and two line outs. As with the other devices we've talked about, it has multiple interfaces: Ethernet, ISDN and POTS. It has an integrated antenna for GSM, or UMTS, or 3g+, and it also has a card expansion slot, and a USB port for other modems such as WiMax or 4G/LTE. It will communicate with other devices via G.711 or G.722, and its N/ACIP compliant. (Typically on the far end you would have another Aeta codec, such as the Scoop 4+.) Other algorithms are MPEG layer 2, AAC, CELP and 4SB ADPCM. Last but not least, you can do recording and simple editing right on the device itself.
Road case or remote truck
It may be time to remove legacy ISDN codecs from road cases and remote broadcast vehicles, and to replace them (or at the very least, supplement them) with AoIP codecs of some flavor.
- continued on page 4
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